[unreadable] The applicant has completed subspecialty training in Nephrology and hopes to pursue a career in basic research focused on human disease. The proposed project would provide an opportunity to broaden her knowledge and experience in molecular and cell biology. Studying the signaling networks involved in actin cytoskeleton regulation by the HIV-1 accessory protein Nef in podocytes should provide an excellent foundation for future independent projects examining the pathogenesis of glomerular disease. This proposal outlines a research plan to investigate the mechanisms leading to actin cytoskeleton deregulation in podocytes in the setting of HIV-1 infection. Preliminary work indicates that Nef leads to deregulation of members of the Rho family GTPases, RhoA and Rac1 in podocytes. The regulatory mechanism by which this occurs including activation of GTPase activating proteins (GAPs) and guanine exchange factors (GEFs) and enhanced degradation will be defined. Cross-talk between Rac1 and RhoA and MAPK1.2 in podocytes will also be explored. Particular emphasis will be placed on defining the role of diaphanous interacting protein (DIP), a recently identified protein with a Nef interacting domain that seems to play a central role in Nef pathogenesis. The experiments outlined will require isolation and maintenance of conditionally immortalized podocyte cultures. Molecular biology techniques including immunoprecipitation, GST pull-down, and Panomics will be used to determine protein-protein interactions and activation states of signaling molecules. Podocyte phenotype will be assessed through immunohistochemistry to visualize the actin cytoskeleton, determination of cell adhesion and podocyte cell counting. Finally, to determine the in vivo function of DIP, animal husbandry, DNA isolation, genotyping, clinical evaluation of mice and tissue collection will be used. The prevalence of HIV-1 infection is increasing and HIVAN remains the leading cause of renal failure in seropositive patients. As this time, no direct therapy for HIVAN is available. Identification of new mediators of HIVAN pathogenesis such as DIP provides information on potential targets for therapy. [unreadable] [unreadable]